Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? (A) Increasing the impeller speed and the volute area (B) Increasing the number of vanes in the impeller (C) Mounting of two or more impellers in series on a single shaft (D) Either of (A), (B) or (C)

Which of the following options will facilitate the achievement of a very
high head (say 30 metres) in case of a centrifugal pump?
(A) Increasing the impeller speed and the volute area
(B) Increasing the number of vanes in the impeller
(C) Mounting of two or more impellers in series on a single shaft
(D) Either of (A), (B) or (C)
by

1 Answer

Answer :

(C) Mounting of two or more impellers in series on a single shaft
by

Related questions

The head developed by a centrifugal pump is largely determined by the (A) Power of the pump(B) Nature of the liquid being pumped(C) Angle of the vanes and the speed of the tip of the impeller(D) Vapour pressure of the liquid

Description : The head developed by a centrifugal pump is largely determined by the (A) Power of the pump (B) Nature of the liquid being pumped (C) Angle of the vanes and the speed of the tip of the impeller (D) Vapour pressure of the liquid

Last Answer : (C) Angle of the vanes and the speed of the tip of the impeller

Which of the following is not the function of a volute casing provided in a centrifugal pump? (A) To reduce the head loss in discharge (B) To increase the pump efficiency (C) To collect liquid from the periphery of the impeller and to transmit it to the delivery pipe at constant velocity (D) To increase the pump discharge rate

Description : Which of the following is not the function of a volute casing provided in a centrifugal pump? (A) To reduce the head loss in discharge (B) To increase the pump efficiency (C) To collect liquid ... and to transmit it to the delivery pipe at constant velocity (D) To increase the pump discharge rate

Last Answer : Option D

A mixed flow centrifugal pump (A) Employs such an impeller, through which the flow is a combination of radial & axial flow (B) Mixes the two fluids before pumping them (C) Pumps the two fluids separately and then mixes them (D) Employs impellers in both the radial & axial directions

Description : A mixed flow centrifugal pump (A) Employs such an impeller, through which the flow is a combination of radial & axial flow (B) Mixes the two fluids before pumping them (C) Pumps the two fluids separately and then mixes them (D) Employs impellers in both the radial & axial directions

Last Answer : (A) Employs such an impeller, through which the flow is a combination of radial & axial flow

Conversion of dynamic velocity head into static pressure head in a centrifugal pump is the result of : (a) Increasing area of flow between adjacent vanes from inlet to outlet (b) Difference in pressure between suction and delivery ends (c) Radial thrust in pumps (d) Stuffing Box

Description : Conversion of dynamic velocity head into static pressure head in a centrifugal pump is the result of : (a) Increasing area of flow between adjacent vanes from inlet to outlet (b) Difference in pressure between suction and delivery ends (c) Radial thrust in pumps (d) Stuffing Box

Last Answer : (b) Difference in pressure between suction and delivery ends

A centrifugal pump is called a turbine pump, if it is having a (A) Turbine type impeller (B) Vaned diffusion casing (C) Rotating vaned volute (D) None of these

Description : A centrifugal pump is called a turbine pump, if it is having a (A) Turbine type impeller (B) Vaned diffusion casing (C) Rotating vaned volute (D) None of these

Last Answer : (B) Vaned diffusion casing

The capacity of a centrifugal pump Can be increased by increasing the (A) Impeller diameter or speed (B) Number of pumps and joining them in series (C) Number of pumps and joining them in parallel (D) All (A), (B) and (C)

Description : The capacity of a centrifugal pump Can be increased by increasing the (A) Impeller diameter or speed (B) Number of pumps and joining them in series (C) Number of pumps and joining them in parallel (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Pick up the correct statement from the following regarding radial flow centrifugal pumps: (A) These are provided with volute type or turbine type casings (B) In involute type of radial flow centrifugal pump, the impeller discharges into a gradually expanding spiral casing (C) The efficiency of turbine type of radial flow centrifugal pump, is always higher than that of volute type (D) All the above

Description : Pick up the correct statement from the following regarding radial flow centrifugal pumps:  (A) These are provided with volute type or turbine type casings  (B) In involute type of radial flow ... centrifugal pump, is always higher than that of  volute type  (D) All the above 

Last Answer : (D) All the above 

In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. (A) Speed of (B) Diameter of (C) Fluid velocity leaving (D) All (A), (B) and (C)

Description : In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. (A) Speed of (B) Diameter of (C) Fluid velocity leaving (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter) (A) 0.5 D (B) D (C) 1.5 D (D) 2 D

Description : Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The ... where, D = impeller diameter) (A) 0.5 D (B) D (C) 1.5 D (D) 2 D

Last Answer : (B) D

Which one of the following types of impeller vanes are most commonly used in centrifugal type compressors? A. Forward curved B. Radial C. Backward curved D. Tangential

Description : Which one of the following types of impeller vanes are most commonly used in centrifugal type compressors? A. Forward curved B. Radial C. Backward curved D. Tangential

Last Answer : ANSWER : C

In case of a, centrifugal pump, the ratio h1/h2is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller). (A) Mechanical (B) Overall (C) Volumetric (D) Impeller

Description : In case of a, centrifugal pump, the ratio h1/h2is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller). (A) Mechanical (B) Overall (C) Volumetric (D) Impeller

Last Answer : A) Mechanical

In centrifugal compressor terminology, vaneless space refers to the space between A. The inlet and blade inlet edge B. Blades in the impeller C. Diffuser exit and volute casing D. Impeller tip and diffuser inlet edge

Description : In centrifugal compressor terminology, vaneless space refers to the space between A. The inlet and blade inlet edge B. Blades in the impeller C. Diffuser exit and volute casing D. Impeller tip and diffuser inlet edge

Last Answer : ANSWER : D

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. (A) NPSH required (B) BHP required by the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)

Description : Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. (A) ... the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

With a constant diameter impeller of a centrifugal pump (A) Its capacity varies directly as the square of speed (B) Head varies as the square of speed (C) Horsepower input varies as the square of speed (D) Head varies as the speed

Description : With a constant diameter impeller of a centrifugal pump (A) Its capacity varies directly as the square of speed (B) Head varies as the square of speed (C) Horsepower input varies as the square of speed (D) Head varies as the speed

Last Answer : (B) Head varies as the square of speed

Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. (A) Radius of (B) Speed of (C) Fluid velocity leaving (D) None of these

Description : Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. (A) Radius of (B) Speed of (C) Fluid velocity leaving (D) None of these

Last Answer : (D) None of these

Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : C) Both (A) and (B)

Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) (A) D = 1840 H0.5 /N (B) D = 1840 N/H0.5 (C) H = 1840 D0.5 /N (D) D = 1840 H/N

Description : Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) (A) D = 1840 H0.5 /N (B) D = 1840 N/H0.5 (C) H = 1840 D0.5 /N (D) D = 1840 H/N

Last Answer : (A) D = 1840 H0.5 /N

At a constant speed of the centrifugal pump, it’s __________ the impeller diameter. (A) Capacity varies directly with (B) Head varies as the square of (C) Horsepower varies as the cube of (D) All (A), (B) and (C)

Description : At a constant speed of the centrifugal pump, it’s __________ the impeller diameter. (A) Capacity varies directly with (B) Head varies as the square of (C) Horsepower varies as the cube of (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Volute type of casing is provided in a centrifugal pump to (A) Convert velocity head to pressure head (B) Convert pressure head to velocity head (C) Reduce the discharge fluctuation (D) Increase the discharge

Description : Volute type of casing is provided in a centrifugal pump to (A) Convert velocity head to pressure head (B) Convert pressure head to velocity head (C) Reduce the discharge fluctuation (D) Increase the discharge

Last Answer : (D) Increase the discharge

Volute of a centrifugal pump should be designed in a fashion, such that the (A) Kinetic head gets converted into static head (B) Moving stream gradually reduces velocity (C) Mean velocity remains constant (D) None of these

Description : Volute of a centrifugal pump should be designed in a fashion, such that the (A) Kinetic head gets converted into static head (B) Moving stream gradually reduces velocity (C) Mean velocity remains constant (D) None of these

Last Answer : (A) Kinetic head gets converted into static head

During agitation of liquids, the (A) Froude number is independent for the curves between power number and Reynolds number in baffled system (B) Power number becomes independent of impellers Reynolds number at high Reynolds number, but is dependent on the geometry of the impeller (C) Froude number is used to account for the effect of surface (e.g., the centre vortex) on the power number (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1

Last Answer : (A) 0.5

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5

Last Answer : (A) 2

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. (A) 500 (B) 200 (C) 1000 (D) 750

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. (A) 500 (B) 200 (C) 1000 (D) 750

Last Answer : (A) 500

Design of the casing of centrifugal pump should be such as to minimise the (A) Back flow through impeller (B) Loss of kinetic head (C) Loss of static head (D) None of these

Description : Design of the casing of centrifugal pump should be such as to minimise the (A) Back flow through impeller (B) Loss of kinetic head (C) Loss of static head (D) None of these

Last Answer : (B) Loss of kinetic head

In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall

Description : In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall

Last Answer : (A) Manometric

Erosion and pits formation on the impeller of a centrifugal pump may be due to (A) Cavitation (B) Low speed of impeller (C) Its operation with delivery valve closed for considerable time after starting the pump (D) Off centering of pump with motor

Description : Erosion and pits formation on the impeller of a centrifugal pump may be due to (A) Cavitation (B) Low speed of impeller (C) Its operation with delivery valve closed for considerable time after starting the pump (D) Off centering of pump with motor

Last Answer : (A) Cavitation

The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump. (A) Electromagnetic (B) Reciprocating (C) Centrifugal (D) Volute

Description : The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump. (A) Electromagnetic (B) Reciprocating (C) Centrifugal (D) Volute

Last Answer : (A) Electromagnetic

Maintenance cost of a __________ pump for a particular duty is the least. (A) Centrifugal (B) Reciprocating (C) Volute (D) Gear

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Last Answer : (A) Centrifugal

To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump. (A) Reciprocating (B) Centrifugal (C) Volute (D) Rotary vacuum

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Centrifugal pump is normally classified on the basis of the (A) rpm (B) Type of casing (C) Impeller blade angle (D) Number of blades in impeller

Description : Centrifugal pump is normally classified on the basis of the (A) rpm (B) Type of casing (C) Impeller blade angle (D) Number of blades in impeller

Last Answer : (B) Type of casing

Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these

Description : Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these

Last Answer : (C) Avoid chances of separation inside the impeller

Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply large quantities of air at a lower pressure ratio C. Centrifugal compressors are used to supply small quantities of air at a lower pressure ratio D. Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.

Description : Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply ... . Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.

Last Answer : ANSWER : B

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump (A) Develops a lower head (B) Capacity is reduced (C) Requires more power (D) All (A), (B) and (C)

Description : A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump (A) Develops a lower head (B) Capacity is reduced (C) Requires more power (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp). (A) Less head & capacity (B) More head (C) More capacity (D) Less head & more capacity

Description : A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp). (A) Less head & capacity (B) More head (C) More capacity (D) Less head & more capacity

Last Answer : (A) Less head & capacity

Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

Description : Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

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The most important factor, which determines the maximum height to which water can be lifted by a pump at standard temperature is the (A) Barometric pressure (B) Speed of the impeller (C) Diameter of the impeller (D) Both (B) and (C)

Description : The most important factor, which determines the maximum height to which water can be lifted by a pump at standard temperature is the (A) Barometric pressure (B) Speed of the impeller (C) Diameter of the impeller (D) Both (B) and (C)

Last Answer : (A) Barometric pressure

A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump. (A) Sump (B) Volute (C) Vacuum (D) Submerged

Description : A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump. (A) Sump (B) Volute (C) Vacuum (D) Submerged

Last Answer : (C) Vacuum

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Last Answer : (A) Monotonically decreases

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades. (A) Inlet tip of a blade curves in a direction opposite to that (B) Outlet tip of a blade curves in a direction opposite to that (C) Inlet tip of a blade is towards the direction (D) Outlet tip of a blade is towards the direction

Description : The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades. (A) Inlet tip of a blade curves in a direction opposite to that (B) Outlet tip ... Inlet tip of a blade is towards the direction (D) Outlet tip of a blade is towards the direction

Last Answer : (D) Outlet tip of a blade is towards the direction

While starting a centrifugal pump, its delivery valve should be kept (A) Opened (B) Closed (C) Either opened or closed; it does not make any difference (D) Either opened or closed; depending on the fluid viscosity

Description : While starting a centrifugal pump, its delivery valve should be kept (A) Opened (B) Closed (C) Either opened or closed; it does not make any difference (D) Either opened or closed; depending on the fluid viscosity

Last Answer : (B) Closed

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Description : Which of the following is the most common pump for pumping either raw sewage or sludge? (A) Electromagnetic pump (B) Centrifugal pump (C) Reciprocating pump (D) Gear pump

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Description : The maximum head that can be developed by a single impeller is __________ ft. (A) 25 (B) 100 (C) 250-300 (D) 1000

Last Answer : (C) 250-300

For the production of very high vacuum, a __________ pump is normally used. (A) Diffusion (B) Centrifugal (C) Jet ejector (D) Piston

Description : For the production of very high vacuum, a __________ pump is normally used. (A) Diffusion (B) Centrifugal (C) Jet ejector (D) Piston

Last Answer : (A) Diffusion

Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have (A) Very low speeds (B) Smaller discharge (C) Higher capital &maintenance cost (D) High vibrations

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Last Answer : (C) Higher capital &maintenance cost

High specific speed of a pump implies that, it is a/an __________ pump. (A) Centrifugal (B) Mixed flow (C) Axial flow (D) None of these

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Description : Which of the following is a boiler accessory i.e., not a boiler mounting? (A) Blow off cock (B) Feed check valve (C) Feed water pump (D) Stop valve

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Minimum horsepower of pump required for filling 50m3 water tank, 20 metres high from ground in 30 minutes by lifting water from a well 5 metres below the ground level is a.5.45 KW b.7.5 KW c.6.81 KW d.Tapered bearing e.66.8 KW

Description : Minimum horsepower of pump required for filling 50m3 water tank, 20 metres high from ground in 30 minutes by lifting water from a well 5 metres below the ground level is a.5.45 KW b.7.5 KW c.6.81 KW d.Tapered bearing e.66.8 KW

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The pressure rise in the impeller of centrifugal compressor is achieved by A. the decrease in volume and diffusion action B. the centrifugal action and decrease in volume C. the centrifugal and diffusion action D. the centrifugal and push pull action

Description : The pressure rise in the impeller of centrifugal compressor is achieved by A. the decrease in volume and diffusion action B. the centrifugal action and decrease in volume C. the centrifugal and diffusion action D. the centrifugal and push pull action

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